In the proposed research, individual differences are parsed on the basis of behavioral and biological parameters theoretically related to affective processing, and the psychometric properties and interrelationships among the behavioral, biological, and self-report measures are examined. Two separable features of affective processing are of particular interest in this project: the positivity offset, and the negativity bias. Prior research in humans has obtained evidence for the operation of a positivity offset and a negativity bias, including studies of impression formation studies, ratings of pictorial stimuli and of trait adjectives, and event-related brain potentials to unexpected pleasant or unpleasant stimuli. The first aim of the proposed research is to extend the prior work to examine the psychometric properties and the convergent and discriminant validity of the positivity offset and negativity bias as measured in these paradigms. The same individuals will be tested on three separate occasions using established paradigms for studying the positivity offset and negativity bias. The second aim is to examine how other biological measures of affective processing, including frontal asymmetry, facial electromyography (EMG), electrodermal lability, and startle probe modulation by and recover from pleasant and unpleasant foregrounds, relate to the behavioral measures of the positivity offset and negativity bias. The third aim is to examine the relationship among self-report and personality measures of affective processing style and (a) the behavioral measures of positivity offset and the negativity bias, as assessed in Aim 1; and (b) biological measures of affective processing, as assessed in Aim 2.